Parallel audit cycles between primary and secondary event feeds

ABSTRACT

Disclosed are embodiments for providing batch performance using a stream processor. In one embodiment, a method is disclosed comprising completing a first audit for a primary event type, the first audit generating a set of primary events and completing a second audit for a secondary event type, the second audit generating a draft set of secondary events and an auxiliary feed of un-joined secondary events. The method then performs a join audit check on the auxiliary feed of un-joined secondary events and a set of flags, each flag in the set of flags indicating that a respective un-joined secondary event was properly joined. Based on the results of the join audit check, the method replays a subset of the un-joined secondary events in the auxiliary feed upon determining that the join audit check failed.

COPYRIGHT NOTICE

This application includes material that may be subject to copyrightprotection. The copyright owner has no objection to the facsimilereproduction by anyone of the patent disclosure, as it appears in thePatent and Trademark Office files or records, but otherwise reserves allcopyright rights whatsoever.

BACKGROUND

In the era of big data processing, data pipelines have become vital toingesting, processing, and outputting large quantities of data at highvelocity and having high variability. In general, a data pipelinecomprises a series of automated processing stages that take raw inputdata and convert the raw input data into a more suitable format forconsumption by downstream computer processing systems.

Various architectures of data pipelines exist, including batch, Lambda,and Kappa architectures. Batch data pipelines process data in “batches”at regular intervals and are suitable for non-critical functionalitywhile providing high reliability of data processing. Batch datapipelines, however, suffer from not being able to process data inreal-time. Thus, a lag behind the ingestion of data and output of usefulinformation or knowledge always exists in a batch data pipeline.

Lambda pipelines utilize a batch processor concurrently with a streamprocessor. In these pipelines, the batch processor processes all datawithin a historical batch while the stream processor “augments” theprocessed batch data with the results of stream processing. Eventually,the batch processor will “re-process” the data processed by the streamprocessor and overwrite the information generated by the streamprocessor. Lambda pipelines are fast, due to the use of streamprocessors; however, they require duplication of processing logic inboth the stream processors and the batch processors. Further, Lambdapipelines use twice the processing hardware due to the use of twoseparate processing paradigms (i.e., stream and batch, which process thedata in the same manner).

Like Lambda pipelines, Kappa pipelines utilize a stream processor.However, Kappa pipelines eschew a batch processor. Kappa pipelinesrequire frequent “re-running” of event streams through the streamprocessor to provide simulated batch performance. Kappa pipelines ensurethat streaming data is processed correctly (e.g., the pipeline does notdrop or duplicate data); however, these pipelines ensure this byre-executing processing and are thus slower than pure streamingpipelines. Further, since Kappa pipelines use stream processingtechniques, there is no method for performing more complex operationssuch as joins or aggregations, since these operations inherently requireaccess to a full (e.g., batch) dataset. That is, stream processorsinherently cannot perform these operations, thus replaying streams doesnot remedy this problem.

BRIEF SUMMARY

This disclosure recognizes a need in the art for a new pipelinearchitecture that provides the advantages of stream processors (e.g.,speed) with the advantages of batch processors (e.g., integrity andcomplex operations). The disclosed embodiments provide these advantagesand solve other problems in existing pipelines.

The disclosed embodiments describe an improved big data processingsystem that uses a stream processing engine with additional hardware andsoftware to harden inaccuracies detected during stream processing.

In one embodiment, a method is disclosed comprising completing a firstaudit for a primary event type, the first audit generating a set ofprimary events; completing a second audit for a secondary event type,the second audit generating a draft set of secondary events and anauxiliary feed of un-joined secondary events; performing a join auditcheck on the auxiliary feed of un-joined secondary events and a set offlags, each flag in the set of flags indicating that a respectiveun-joined secondary event was properly joined; and replaying a subset ofthe un-joined secondary events in the auxiliary feed upon determiningthat the join audit check failed.

In another embodiment, an apparatus is disclosed comprising: aprocessor; and a storage medium for tangibly storing thereon programlogic for execution by the processor, the stored program logic causingthe processor to perform the operations of: completing a first audit fora primary event type, the first audit generating a set of primaryevents; completing a second audit for a secondary event type, the secondaudit generating a draft set of secondary events and an auxiliary feedof un-joined secondary events; performing a join audit check on theauxiliary feed of un-joined secondary events and a set of flags, eachflag in the set of flags indicating that a respective un-joinedsecondary event was properly joined; and replaying a subset of theun-joined secondary events in the auxiliary feed upon determining thatthe join audit check failed.

In another embodiment, a non-transitory computer-readable storage mediumfor tangibly storing computer program instructions capable of beingexecuted by a computer processor, the computer program instructionsdefining the steps of: completing a first audit for a primary eventtype, the first audit generating a set of primary events; completing asecond audit for a secondary event type, the second audit generating adraft set of secondary events and an auxiliary feed of un-joinedsecondary events; performing a join audit check on the auxiliary feed ofun-joined secondary events and a set of flags, each flag in the set offlags indicating that a respective un-joined secondary event wasproperly joined; and replaying a subset of the un-joined secondaryevents in the auxiliary feed upon determining that the join audit checkfailed.

The illustrated embodiments provide numerous benefits over existingpipelines. The disclosed embodiments reduce data processing andcertification times by certifying events using a stream processor versusa batch processor. Thus, the illustrated embodiments, do not require a“waiting” period prior to certifying results and can certify results inreal-time or near real-time. The disclosed embodiments additionallyutilize a single pipeline and thus do not require the hardwareduplication, software complexity, and human resources required by Lambdapipelines. Relatedly, since application-level code must only be deployedonce, rapid changes in data processing can be implemented withoutrequiring separate development workflows. Additionally, since only onecodebase is used, there is no risk of variations in processing betweenpipelines. Finally, in existing pipelines, sacrifices for speed can leadto a more significant variation between the initially posted resultsfrom the streaming pipeline and the final results from batch processing.As the latency of batch increases relative to streaming, this can leadto a lack of confidence in reporting as the variation becomes morepronounced. The disclosed embodiments alleviate this deficiency.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A is a block diagram illustrating a processing system employing aLambda architecture.

FIG. 1B is a block diagram illustrating a processing system employing aKappa architecture.

FIG. 2 is a block diagram illustrating a data processing systemaccording to some embodiments of the disclosure.

FIG. 3 is a block diagram illustrating a pipeline factory according tosome embodiments of the disclosure.

FIG. 4 is a block diagram illustrating a core pipeline according to someembodiments of the disclosure.

FIG. 5 is a block diagram illustrating an alternative auditor systemaccording to some embodiments of the disclosure.

FIG. 6A is a flow diagram illustrating a method for performing aparallel audit of events according to some embodiments.

FIG. 6B is a flow diagram illustrating a method for performing a jointaudit check according to some embodiments.

FIG. 7 is a schematic diagram illustrating a computing device showing anexample embodiment of a client or server device used in the variousembodiments of the disclosure.

DETAILED DESCRIPTION

FIG. 1A is a block diagram illustrating a processing system employing aLambda architecture.

In the illustrated embodiment, events in the system (100 a) originatefrom one or more event emitters (102). As used herein, an event refersto any type of data generated by a computing system. Generally, mostevents include arbitrary data as well as a timestamp indicating when theevent emitter (102) generated the data. Alternatively, or in conjunctionwith the preceding, the system (100 a) adds a timestamp representing thetime the pipelines (106, 108) receive the event. In some embodiments,the timestamp comprises a standard time (e.g., based on a 24-hourclock). In some embodiments, the timestamp comprises a numerical value(e.g., time since UNIX epoch). In other embodiments, the timestamp maycomprise a sequence number or other incrementing (or otherwise changing)value. In some embodiments, events further include nonce values toensure uniqueness.

The event emitters (102) can comprise any computing system capable ofgenerating data. The disclosure places no limitations on the type ofdata or type of systems capable of generating such data. As one example,an event emitter may include a digital analytics system configured totrack and monitor user events on webpages or in mobile apps. A digitalanalytics platform generates many events as users access products. Oneexample is the delivery of advertising creatives. In these scenarios,the analytics platform generates an event indicating that a servertransmitted the creative to the end-user. The analytics platform alsogenerates an event indicating that the end-user device displayed thecreative (i.e., an impression). If the end-user interacts with thecreative, the analytics platform generates a “click” event (which may beany type of interaction including touch events and thus is not limitedto physical mouse clicks). In certain embodiments, the analyticsplatform also generates conversion events that indicate that after animpression, and after a click, the end-user has completed another action(e.g., completes a digital purchase) that is related to the previousevents. In some embodiments, the analytics platform tracks all of theseevents via a client-side identifier stored in, for example, a cookie orother end-user storage mechanism.

In some embodiments, event emitters (102) are part of the system (100a). That is, in some embodiments, the system (100 a) includes and hassome level of control over the event emitters (102). Examples of thistype of arrangement include internal data sources for an organization(e.g., internal analytics tracking). In other embodiments, the eventemitters (102) comprise third-party systems. In some embodiments, thesystem (100 a) receives events from both internal and external eventemitters (102).

In either scenario, event emitters (102) transmit events over atransport layer (104). The transport layer (104) comprises one or morenetwork protocols and one or more physical media used for transportingdata. The disclosure does not unduly limit the structure of thetransport layer. In some embodiments, the system (100 a) uses anInternet protocol suite (e.g., transmission control protocol (TCP) andInternet protocol (IP)) as the transport layer (104). The system (100 a)may use other models such as those adhering to the Open SystemsInterconnection (OSI) model or other types of protocol models. In someembodiments, the transport layer (104) performs other operations on theevents beyond network routing (e.g., TCP/IP). For example, the transportlayer (104) may compress events using, as an example, gzip or othercompression algorithms.

The specific internal workings of the transport layer (104) are notlimiting, and the system (100 a) may ignore various features of thetransport layer (104) that are handled entirely in the transport layer(e.g., congestion control in a TCP layer). However, as discussed in moredetail herein, the transport layer (104) may include inherent datatransfer characteristics that impact the processing of the data bysystems. One example, discussed in more detail in FIG. 2 et seq, is thatsome transport layer (104) designs may unintentionally (or, in somecases, intentionally) duplicate events transmitted over a network. Insuch networks, the event emitters (102) transmit one event, but thepipelines (106, 108) receive two or more events. A more concrete exampleof such a transport layer is a publish-subscribe system such as Apache®Kafka, which can provide “at least once” delivery of events.

As illustrated, the system (100 a) routes events from the transportlayer (104) to both a streaming pipeline (106) and a batch pipeline(108). In the illustrated embodiment, the batch pipeline (108) processesdata in batches. As used herein, a batch refers to a period in which thebatch pipeline (108) analyzes data (e.g., every hour). The disclosuredoes not describe the specific inner workings of the batch pipeline(108) in detail; however, the batch pipeline (108) comprises anyprocessing system that provides accurate processing of data. Examples ofbatch pipelines include Hadoop clusters. The batch pipeline (108)ensures this accuracy by running slowly and at fixed intervals uponreceiving all needed data. Since the batch pipeline (108) requires afixed period of data (e.g., one hour) and a second fixed period toprocess the data (e.g., three hours), the batch pipelines (108) areconsistently “behind” the current time. That is, when the batch pipeline(108) writes data to the data warehouse (110), the data written is“stale” by a fixed amount of time (e.g., four hours in the previousexamples). However, as stated above, consumers of the batch-processeddata can be confident that the data is accurate.

As a brief aside, before Lambda systems, big data systems often onlyincluded a batch pipeline (108) and did not include a streaming pipeline(106). As a result, such systems produced consistently delayed results.To remedy this delay, the system (100 a) includes a streaming pipeline(106). Such a pipeline may comprise one or more stream processors suchas Apache® Storm processors or similar stream processors. In contrast tothe batch pipeline, the streaming pipeline (106) processes data inreal-time or near real-time. Thus, when the streaming pipeline (106)receives an event over the transport layer (104), it immediatelyprocesses or transforms the event and writes the processed event to thedata warehouse (110).

Since the streaming pipeline (106) processes events quickly and inisolation, the streaming pipeline (106) may introduce errors in theprocessed data. For example, the streaming pipeline (106) generally doesnot guard against writing duplicate data if the pipeline (106) receivesduplicate events. Similarly, the streaming pipeline (106) mayinadvertently drop some events. Thus, the streaming pipeline (106) isfast but inaccurate.

In the illustrated embodiment, the data warehouse (110) segments datareceived from the streaming pipeline (106) and the batch pipeline (108)into two separate storage areas. Additionally, as the batch pipeline(108) “catches up” to the data processed by the streaming pipeline(106), the data warehouse (110) overwrites the results of the streamingpipeline (108). Thus, at any given moment, the data warehouse (110)stores accurate, batch-processed data and a smaller, more recent subsetof inaccurate stream-processed data. Absent system failures, the sizesubset of the inaccurate data remains constant while the size of theaccurate data increases over time.

To support the above format of the data warehouse, the system (100 a)must duplicate logic between the streaming pipeline (106) and the batchpipeline (108). Since the streaming results must be “reconciled” withthe results of the batch processing, the streaming pipeline (106) andbatch pipeline (108) must process the events in the same manner. Thisrequirement doubles both the development time and the computingresources needed to support both pipelines (106, 108). Additionally, thesystem (100 a) requires additional software and hardware to enable thedata warehouse (110) to perform the reconciliation process after thecompletion of each batch processing job.

FIG. 1B is a block diagram illustrating a processing system employing aKappa architecture. The illustrated system (100 b) solves some of theproblems of Lambda architectures, as discussed in the preceding figure.However, the system (100 b introduces additional problems and fails toprovide full batch support.

Various elements of the system (100 b) are identical, or nearlyidentical, to those similarly numbered elements of FIG. 1A. The eventemitters (102) and the data transport layer (104) perform the samefunctions as previously described. Also, the streaming pipeline (106)may perform many, if not all, of the same operations of the streamingpipeline (106) discussed in FIG. 1A.

As illustrated, the streaming pipeline (106) receives events generatedby the event emitters (102) over the data transport layer (104). Thestreaming pipeline (106) processes this data and writes the processeddata to the data warehouse (116). In contrast to the data warehouse(110) in FIG. 1A, the data warehouse (116) may only include a singlestorage area for data given the absence of a batch processing layer.

As described in the description of the previous system (100 a),streaming pipelines (106) generally cannot guarantee the accuracy ofdata processing. Some systems (e.g., 100 b) remedy this problem byemploying “micro batching” whereby small batches of stream events areprocessed simultaneously. In general, these batches representmilliseconds of events, thus providing reasonable speed while simulatingsmall batches. Micro-batching, however, fails to provide the level ofaccuracy provided by larger (e.g., one hour) batches. Another techniqueuses recompute logic (114) to re-process streaming events when the logicof the streaming pipeline (106) changes or based on other requirements.In this scenario, the system (100 b) can store raw events in the rawevents storage module (112), the recompute logic (114) retrieves theseevents. The recompute logic (114) then streams the events into thestream pipeline (106) for re-processing. In one scenario, the recomputelogic (114) executes when the system (100 b) changes the processinglogic of the streaming pipeline. Thus, if the system (100 b) modifieshow the streaming pipeline (106) processes events, the recompute logic(114) simulates a historical event stream. In another embodiment, therecompute logic (114) can stream data from the raw events storage module(112) to the streaming pipeline (106) at fixed intervals, thussimulating a batch processing mode. However, there are numerouschallenges to this approach that limit its effectiveness. First, datafrom the raw events storage module (112) must be re-streamed in the sameorder as streamed initially, to ensure the integrity of there-processing. Thus, the recompute logic (114) reproduces inaccuraciesrelating to out-of-order events during the re-streaming. Second, theinfrastructure that supports the streaming pipeline (106) generallycannot handle significant increases in streaming data, thus limiting thetotal amount of re-streamed data the streaming pipeline (106) can handleat any given time. Third, and most importantly, the streaming pipeline(106) cannot inherently perform various operations that a batch pipeline(108) can perform, such as joins or aggregations. Thus, even ifre-streamed, the output of the streaming pipeline (106) always lacksthese advanced operations.

FIG. 2 is a block diagram illustrating a data processing systemaccording to some embodiments of the disclosure.

The illustrated system (200) segments the data processing into multiplelogical layers. In some embodiments, these layers may also comprisephysical layers, with each layer physically connected via a networkinterconnect. The illustrated layers comprise serving (220 a), datatransport (220 b), pipeline factory (220 c), packaging (220 d), andwarehousing (220 e) layers.

The serving layer (220 a) includes one or more event emitters (202). Inthe illustrated embodiment, these event emitters (202) can be similar oridentical to the event emitters (102) discussed previously. As a fewexamples, the event emitters (202) can comprise systems including, butnot limited to, ad servers, web servers, and beacon servers, thatproduce raw traffic events and send the events factory layer (220 c) viathe data transport layer (220 b). In the illustrated embodiment, thedata transport layer (220 b) represents the previously described datatransport (204). In the illustrated embodiment, the data transport layer(220 b) comprises multiple network topologies and protocols that, whencombined, deliver events to the factory layer (220 c).

In the illustrated embodiment, the factory layer (220 c) receives rawevents from the data transport layer (220 b) and processes the eventsvia a core pipeline (210). The description of FIG. 3 provides furtherdetail regarding the factory layer (220 c), and the description of FIG.4 provides further detail regarding the core pipeline (210). Thus, thefollowing description of the factory layer (220 c) only brieflydescribes the layer (220 c) and the core pipeline (210), and FIGS. 3 and4 present further detail.

The factory layer (220 c) is responsible for doing the bulk of theprocessing of event traffic via the core pipeline (210). The followingdescription describes exemplary processing operations performed by thecore pipeline (210). The core pipeline (210) may perform some or all ofthe following operations as well as additional operations.

In one embodiment, in the serving (220 a) and data transport (220 b)layers, devices often compress and bundle data to conserve bandwidth. Asa result, the core pipeline (210) may perform a parsing operation thatunpacks or processes complex data structures (e.g., blobs) so thatdownstream consumer systems can access the data. Thus, as one example,the core pipeline (210) can detect that an incoming event was compressedusing a gzip algorithm and may first unzip the event.

In another embodiment, the core pipeline (210) performs explosionoperations. An explosion operation comprises unpacking composite events.For example, a multi-serve event comprises an event indicating that anend-user device received a set of content to be displayed. Thus, themulti-serve event comprises a data structure describing multiple itemsof content (e.g., advertisements). The core pipeline (210) may transforma single multi-serve event into multiple single-serve events such thateach item of content in the event is associated with an independentevent for later processing.

In another embodiment, the core pipeline (210) performs metadataannotation operations. As illustrated, the core pipeline (210)communicates with a metadata store (208). In one embodiment, themetadata store (208) comprises a data storage device such as a MySQLdatabase or other type of relational database. In other embodiments, themetadata store (208) may comprise other types of data storage devices(e.g., a key-value data store). The core pipeline (210) accesses themetadata store (208) to perform dimensional annotation on incoming eventdata. As used herein, dimensional annotation refers to the augmenting ofdata with additional other data. For example, a content serving eventcan be only a line item identifier identifying the served content. Thecore pipeline (210) may access the metadata store (208) and look up aparent insertion order, an advertiser identifier, and an organizationfor that line item identifier. The core pipeline (210) may then augmentthe line item identifier with this metadata to generate an annotatedevent. In this way, downstream consumer systems can group and aggregatebased on the line item identifier.

In another embodiment, the core pipeline (210) performs trafficannotations. A traffic annotation comprises a complex join of an eventwith a prior event. For example, a click event may need to be joinedwith a first impression event to annotate the click with auctioninformation or targeting information that is only available in the firstimpression.

In another embodiment, the core pipeline (210) performs arbitrarycomputations dictated by business logic. An example of this type ofcomputation is a currency conversion. By doing the operation only oncein the core pipeline (210), the system (200) can ensure consistencyacross all subsequent consumer systems, rather than requiring downstreamconsumer systems to implement the same rules and possibly arrive atdifferent results.

In another embodiment, the core pipeline (210) validates incomingevents. In this embodiment, the core pipeline (210) can filter eventsbased on traffic conditions.

In another embodiment, the core pipeline (210) performs deduplication onincoming events. As discussed previously, the data transport layer (220b) may support “at least once” semantics. Alternatively, or inconjunction with the preceding, event emitters may allow duplicateevents. Regardless of the source of duplication, the core pipeline (210)ensures that all events are processed and stored once and notduplicated. For example, the core pipeline (210) may allow more than oneclick event per impression event during a given period.

In another embodiment, the core pipeline (210) performs normalization onthe received events. During a normalization operation, the core pipeline(210) “fits” an event to a particular schema or layout to facilitatereporting. This schema or layout is typically a standard field alignmentand transformation.

Finally, in some embodiments, the core pipeline (210) performs a fastfeedback operation. In this operation, the core pipeline (210) providesfeeds or streams of data at very low latency to low-latency consumers(206) such as an ad serving budget control system. Typically, mostconsumer systems wait until the core pipeline (210) has completed allprocessing steps; however, some consumer systems are willing tosacrifice quality for timing. These specialty stages can be critical tosome consumer systems.

In general, the core pipeline (210) processes events linearly: thequality of the event data increases as data passes from one processingoperation to the next. Ultimately, after the core pipeline (210) appliesall operations to the event data, the core pipeline (210) writes theprocessed event to one or more fact feeds (212). In the illustratedembodiment, a fact feed (212) comprises a log of every event that wasreceived by the core pipeline (210) and any additional information thatthe core pipeline (210) annotates or computes. The fact feeds (210)become the source of truth for the entire system (200). By having thecore pipeline (210) compute the fact feed (212) used by subsequentconsumers pipelines (214 a, 214 b, 214 n), the overall quality of thesystem (200) is improved.

Since the system uses a centralized fact feed (212), the core pipeline(210) never removes any field from an event. Additionally, the corepipeline (210) does not modify any raw field that it receives from thecore pipeline (210) from the data highway (204). However, as oneexception, the core pipeline (210) may replace null or empty fields witha static or default value, as this may assist downstream consumersystems (214 a, 214 b, 214 n). In most embodiments, the core pipeline(210) does not attempt to “correct” or “fix” invalid values in an event.However, the core pipeline (210) may deviate from this requirement torecover from failed launches or bugs. In some embodiments, if the corepipeline (210) violates this requirement and fixes an invalid value inan event, the core pipeline (210) annotates the record with a flag sothat a downstream consumer system can monitor the rule.

Importantly, the core pipeline (210) also ensures that no event isduplicated in the final fact feed (212). Thus, the core pipeline (210)never intentionally duplicates or allows duplicate events to result fromthe operations.

In the illustrated embodiment, the packaging layer (220 d) comprisesvarious consumer pipelines (214 a, 214 b, . . . 214 n) retrieve orreceive data from the fact feed (212). The packaging layer (220 d)accesses the fact feed (212) and provides the processed events thereinto downstream consumer pipelines (214 a, 214 b, . . . 214 n). Whereasthe factory layer (220 c) is typically a complex, but linear processingstage, the packaging layer (220 d) is typically composed of multipleparallel consumer pipelines (214 a, 214 b, . . . 214 n). Consumerpipelines (214 a, 214 b, . . . 214 n) are typically minimal, possiblysingle-stage pipelines that project and aggregate the events in the factfeed (212) for loading into a warehouse (e.g., 218 a, 218 b, . . . 218n) or similar system. The availability of the fact feed (212) triggersconsumer pipelines (214 a, 214 b, . . . 214 n), and thus the consumerpipelines (214 a, 214 b, . . . 214 n) may run in parallel with oneanother.

In some instances, the consumer pipelines (214 a, 214 b, . . . 214 n)are external to the factory layer (220 c) and warehouse layer (220 e).In other instances, the system (200) includes and controls the consumerpipelines (214 a, 214 b, . . . 214 n). Alternatively, or in conjunctionwith the preceding, the warehousing layer (220 e) may be external to thesystem (200). In various embodiments, the consumer pipelines (214 a, 214b, . . . 214 n) generally perform some or all of the followingoperations (or combinations thereof).

In one embodiment, the consumer pipelines (214 a, 214 b, . . . 214 n)perform mapping and transformation operations. In these operations, theconsumer pipelines (214 a, 214 b, . . . 214 n) may require the data in aformat different than the format of the fact feed (212). For example,the consumer pipelines (214 a, 214 b, . . . 214 n) may map enumeratedvalues (possibly in a lossy fashion) to fit a further downstreamconsumer data model.

In another embodiment, the consumer pipelines (214 a, 214 b, . . . 214n) perform projection operations. In some embodiments, consumerpipelines (214 a, 214 b, . . . 214 n) will typically not require everyfield of the fact feed (212). Thus, the consumer pipelines (214 a, 214b, . . . 214 n) only ingest a small fraction of the available columns.

In another embodiment, the consumer pipelines (214 a, 214 b, . . . 214n) perform aggregation operations. In some embodiments, the consumerpipelines (214 a, 214 b, . . . 214 n) aggregate facts and produce metricfields for efficient loading into a database or similar data store.

In another embodiment, the consumer pipelines (214 a, 214 b, . . . 214n) perform reverse annotation joins (e.g., right outer joins). In someembodiments, the consumer pipelines (214 a, 214 b, . . . 214 n) performjoin operations that cannot be implemented efficiently within the corepipeline (210). For example, a data science consumer pipeline mayrequire a feed containing every impression event joined to any futureclick events recorded in the fact feed (212). Because this type ofpipeline requires data collected over a long period before processingcan begin, it would negatively impact all consumer pipelines (214 a, 214b, . . . 214 n) to wait. Therefore, the pipeline performs these joins inbatch outside of the core pipeline (210).

In another embodiment, the consumer pipelines (214 a, 214 b, . . . 214n) perform rollup operations. In some embodiments, the consumerpipelines (214 a, 214 b, . . . 214 n) may choose to create rollup feedsof the raw facts stored in fact feed (212). For example, the consumerpipelines (214 a, 214 b, . . . 214 n) may create an hourly feed from afive-minute fact feed. The consumer pipelines (214 a, 214 b, . . . 214n) may perform this operation to use fewer filenames in a distributefiled system (e.g., the Hadoop Filesystem, HDFS) since such a filesystem collapses multiple files into larger single files. Further, therollup may typically transform the data into a columnar format likeOptimized Row Columnar (ORC) to promote faster ad hoc projection.

In another embodiment, the consumer pipelines (214 a, 214 b, . . . 214n) perform sketch operations. In some embodiments, as the consumerpipelines (214 a, 214 b, . . . 214 n) generate aggregates, the consumerpipelines (214 a, 214 b, . . . 214 n) may produce aggregate sketchcolumns to capture unique users or similar complex computations. Theconsumer pipelines (214 a, 214 b, 214 n) can perform this expensiveoperation once on behalf of multiple end-users or downstream systems.

In another embodiment, the consumer pipelines (214 a, 214 b, . . . 214n) perform cleansing operations. In some embodiments, the consumerpipelines (214 a, 214 b, . . . 214 n) may cleanse data in the fact feed(212) for a specific purpose. For example, cookies or personallyidentifiable information (PII) might need to be anonymized, or theconsumer pipelines (214 a, 214 b, . . . 214 n) may need to obscure datato enforce data visibility controls.

In some embodiments, the consumer pipelines (214 a, 214 b, . . . 214 n)can be hierarchal. That is, a first consumer pipeline may perform one ormore shared steps, and downstream consumer pipelines use the output ofthe first consumer pipeline as input.

After processing by consumer pipelines (214 a, 214 b, . . . 214 n), eachof the consumer pipelines (214 a, 214 b, . . . 214 n) output furtherprocessed event data to respective data warehouses (218 a, 218 b, . . .218 n) in the warehousing layer (220 e). The warehousing layer (220 e)is generally the final stage of the system (200), where data is loadedinto various systems to facilitate reporting, billing, or analysis. Adata team may be responsible for various aspects of the warehousing, orit may be delegated to a data customer instead. Operations for a datateam include loading, replication, and verification. In loadingoperations, the system (200) may need to load the data into a datawarehouse (e.g., an Oracle or Druid data warehouse) or place the dataonto a shared drop box or similar system. In replication operations, thesystem (200) may need to replicate a data feed to another dataprocessing (e.g., Hadoop) cluster in a different co-location. In averification operation, the system (200) may need to verify that thedata loaded into a warehouse (218 a, 218 b, . . . 218 n) accuratelymatches the original fact feed (210) (i.e. certify there was no dataloss).

As illustrated, in some embodiments, data bypasses the packaging layer(220 d). In these embodiments, the core pipeline (210) streams outputdirectly to a real-time data warehouse (216). In the illustratedembodiment, the real-time data warehouse (216). In the illustratedembodiment, the system (200) may use a real-time data warehouse (216)for reporting or similar functions that do not require high dataaccuracy.

FIG. 3 is a block diagram illustrating a pipeline factory according tosome embodiments of the disclosure.

In the illustrated embodiment, a data highway (204) delivers events fromone or more event emitters (not illustrated) to a factory layer (220 c)and raw event storage (302). The description of FIG. 2 provides furtherdetail regarding the data highway (204) which is not repeated herein.

In the illustrated embodiment, the raw event storage (302) may comprisea distributed file system (e.g., HDFS). In one embodiment, the system(300) writes raw events to the raw event storage (302) as they arereceived. In some embodiments, the system (300) writes the raw events toraw event storage (302) in a batch mode. That is, the system (300)writes a separate file for each batch period (e.g., one hour), the fileincluding all events received during that period. In some embodiments,not illustrated, external consumer systems can access the raw eventstorage (302) to perform batch processing. Thus, in some embodiments,the raw event storage (302) can be used to provide backwardscompatibility with existing batch pipelines.

As illustrated, a stream processor (304) receives events from the datahighway (204). In one embodiment, the stream processor (304) comprises adistributed stream processor. In one embodiment, the stream processor(304) comprises a streaming topology that defines data processing stagesto perform on events.

One example of a stream processor (304) is an Apache® Storm topology.Briefly, a Storm topology is a graph of inputs and processing nodes. Thetopology receives events as input streams. Each event in the inputstream comprises a tuple and the input stream itself is an unboundedseries of such tuples. The topology receives streams from input sources,referred to as “spouts.” The topology performs all processing inindividual processing nodes, referred to as “bolts.” The topologydefines the input to a bolt as either a spout or another bolt. Thus, thetopology defines connects between spouts and bolts. The output of one ormore bolts forms the output of the topology.

In the illustrated embodiment, the stream processor (304) performs anyor all of the processing operations described in the description of corepipeline (210) in FIG. 2. Details of these operations are not repeatedherein. Importantly, the stream processor (304) ensures that a givenevent received over the data highway (204) is output at most once to thestreaming queue(s) (306). Thus, during processing, the stream processor(304) detects and drops any duplicated events. FIG. 4 provides furtherdetail regarding specific techniques for performing this detection anddropping.

As illustrated, the stream processor (304) outputs the processed andde-duplicated event stream to one or more streaming queues (306). In oneembodiment, the streaming queues (306) comprise one or more Apache®Kafka queues. Since the event stream is processed by the streamprocessor (304), the data stored in the streaming queues (306) can beconsidered as source of truth for downstream consumers. Thus, alow-latency consumer system (206) can directly access the streamingqueues (306). In this manner, the system (300) can simulate a fullystreaming pipeline. As will be discussed, since the stream processor(304) processes the event stream and ensures that no records are droppedor duplicated, the simulated stream in the streaming queues (306) ismore accurate than a raw event stream. Furthermore, as will bediscussed, the output of the stream processor (304) includes the resultsof more complicated or advance operations (e.g., joins or dimensionalannotation) which are not possible using traditional stream processingtechniques.

A spooler (308) and auditor (310) use the output of the stream processor(304) to support advanced operations by the stream processor (304). FIG.4 provides more detail regarding the spooler (308) and reference is madeto that description.

In one embodiment, the spooler (308) comprises a second streamprocessor. The spooler (308) ensures that a one-to-one mapping betweenstreamed data and data written to the fact feed (210) exists. Thespooler (308) also ensures that streaming events retrieved from thequeues (306) appears exactly once in the fact feed (210) (i.e., noevents in the queues, 306, are duplicated). As such, the spooler (308)may comprise a separate stream topology similar to the stream processor(304). In contrast to the stream processor (304), the spooler (308)reads events from the streaming queues (306). Thus, the event stream tothe spooler (308) comprises the processed events. As illustrated, priorto writing to the fact feed (210), the spooler (308) outputs to theauditor (310) via a buffer (312). In one embodiment, the output of thespooler (308) comprises a flat file (e.g., an HDFS file) and the buffer(312) comprises a distributed file system such as HDFS. In oneembodiment, this flat file comprises a set of events occurring in agiven batch period. Thus, the flat file simulates batch processing, butusing the streaming events.

In the illustrated embodiment, an auditor (310) receives the output ofthe spooler (308). As described above, in some embodiments, the outputof the spooler (308) comprises a batch file of events. In theillustrated embodiment, the auditor (310) also accesses raw eventstorage (302). In one embodiment, the format of the raw event storage(302) and the output of the spooler (308) are the same. For example,spooler (308) may write flat files to HDFS buffer (312) and raw eventstorage (302) may comprise raw events stored in the same type of file(e.g., HDFS). In the illustrated embodiment, the auditor (310) retrievesa batch file from buffer (312). In one embodiment, this batch file isassociated with a fixed period. In some embodiments, this fixed periodis represented in the filename or in metadata. Using this fixed period,the auditor (310) then retrieves a set of events from the raw eventstorage (302) matching the fixed period. In one embodiment, the periodsof the buffer (312) and the raw event storage (302) are synchronized. Inthis embodiment, the auditor (310) then retrieves a single file from theraw event storage (302) that matches the period pulled from the buffer(312). In other embodiments, the auditor (310) may execute a MapReducejob to identify events split across multiple files. In this embodiment,the periods represented by files in the raw event storage are notsynchronized with the buffer (312). Thus, the auditor (310) must patchtogether portions of multiple files stored in raw events storage (302)to rebuild a period of raw events matching the period stored in thebuffer (312). In either event, the auditor (310) receives two filescontaining raw events from raw event storage (302) and a set ofprocessed events for the same period stored in buffer (312).

In general, the auditor (310) ensures that each processed event in thebuffer (312) matches a raw event stored in raw event storage (302).Thus, the auditor (310) ensures that no events were dropped duringprocessing by the stream processor (304) and that no events wereduplicated. If the auditor (310) detects that an event exists in the rawevent storage (302) and does not exist in the corresponding buffer (312)output, the auditor (310) sends the missing event back to the streamprocessor (304) for re-processing.

The stream processor (304) reprocesses the events using the sameprocessing logic used to process the event originally. In someembodiments, the stream processor (304) may add a field to thereprocessed event to indicate it was (or will be) reprocessed. In mostembodiments, the stream processor (304) will properly process the eventduring re-processing. However, if the stream processor (304) cannotreprocess the event (as detected by the auditor, 310), the system (300)may gracefully handle the error. In one embodiment, the auditor (310)can itself add a field to the raw event indicating that the raw eventwas not processed and write the event along with the processed events.

After any missing events are re-processed, the auditor (310) writes thefinal output to the fact feed (210). Since spooler (308), buffer (312)and auditor (310) operate on batches of events, the fact feed (210)comprises a simulated batch data store. In some embodiments, the auditor(310) will delay writing to the fact feed (210) until any events arere-processed. In other embodiments, the auditor (310) writes thepartially final output file to the fact feed (210) and updates the fileupon completing the re-processing.

FIG. 4 is a block diagram illustrating a core pipeline according to someembodiments of the disclosure. Various elements of FIG. 4 are describedin the previous figures and those elements are not described againherein.

In the illustrated embodiment, a stream processor (304) receives eventsfrom a data highway (204). In the illustrated embodiment, the streamprocessor (304) receives events from the data highway (204) via aninitial spout (404). The stream processor (304) as illustrated includestwo separate spouts (404, 422). In the illustrated embodiment, thestream processor (304) utilizes two spouts (404, 422) to distinguishbetween event streams (e.g., original versus re-processing). In theillustrated embodiment, the stream processor (304) topology can beconfigured to add additional extract-transform-load (ETL) steps (e.g.,bolts) for the reprocessing spout (422) versus events received via theinitial spout (404).

In the illustrated embodiment, the stream processor (304) processesevents received via spouts (404, 422) via ETL logic (406). As describedpreviously, ETL logic (406) may comprise a series of linear processingstages (e.g., bolts) for each operation performed on events.

In the illustrated embodiment, the ETL logic (406) outputs processedevents to two streaming queues (408 a, 408 b). In one embodiment, thetwo queues (408 a, 408 b) store varying types of event data. Asillustrated, a first queue (408 a) is accessed by a partial streamconsumer system (424). In the illustrated embodiment, the first queue(408 a) may be filled by the ETL logic (406) prior to the execution ofall processing steps. In the illustrated embodiment, the ETL logic (406)may eschew more complicated and time-consuming operations and interruptthe full processing steps to provide low latency operations. In someembodiments, this bypassing includes foregoing joins, trafficprotection, annotation, etc. In the illustrated embodiment, the partialstream consumer system (424) may comprise a fast feedback system such asbudget or pacing systems that are willing to accept a certain level oferror. Thus, the first queue (408 a) provides “best effort” data whereinthe system (400) does not guarantee the accuracy of the data. Inpractice, however, the system (400) will generally process a largeamount of data correctly enough that the best effort data in the firstqueue (408 a) is of value to the partial stream consumer system (424).

In contrast to the first queue (408 a), the stream processor (302) fillsthe second queue (408 b) with the results of the full ETL processing.Thus, the ETL logic (406) fully processes the data in the second queue(408 b), including performing joins, deduplication, annotations, frauddetection, traffic protection, etc. In one embodiment, the completestreaming consumer system (426) access second queue (408 b) can retrievedata that achieves close to exactly once performance (that is, no eventsare dropped or duplicated) since the data was fully processed in the ETLlogic (406). In some embodiments, this performance will meet “exactlyonce” performance. However, in other embodiments, the output of thesecond queue (408 b) is still subject to inaccuracies caused by theunderlying messaging queue. In some embodiments, a near exactly onecompleteness from second queue (408 b) comprises a 99.9% guarantee ofcompleteness. Such a confidence level is often suitable for applicationssuch as real-time reporting.

Finally, as illustrated and discussed above, a final fact feed (210)meets exactly once requirements of all systems and provide batch-likeperformance. That is, data in the fact feed (210) will be fullyde-duplicated and ensure that no events were dropped. As discussed inFIG. 3, this guarantee is implemented via spooler (308) and auditor(310). Auditor (310) is described more fully in FIG. 3 and those detailsare incorporated herein by reference.

In the illustrated embodiment, the spooler (308) is illustrated asincluding deduplication writer (412), deduplication store (414), and afact feed writer (416).

In the illustrated embodiment, the deduplication writer (412) receivesevents from the second queue (408 b). An event is uniquely identified byan event identifier (event_id). The spooler (308) considers two eventsas duplicates if they have the same event identifier. Events may includeadditional, but standardized, fields such as a type, timestamp, joinstatus, and secondary event identifiers.

The deduplication writer (412) writes each of the events todeduplication store (414). In one embodiment, the store (414) comprisesa database such as HBase or a similar storage device. Upon receiving anevent, the writer (412) analyzes the fields associated with the event.If the event includes one or more secondary event identifiers, thewriter (412) will retrieve all events stored in store (414) matchingthese secondary event identifiers and update the entries to indicatethat a primary event is available (i.e., will be written to the store,414). The writer (412) will then write the received event to the store(414) using the event identifier as a key. In some embodiments, a saltwill be added to the event identifier before using the event identifieras a key. In the illustrated embodiment, the writer (412) will not writethe event if the event has secondary event identifiers and the initialstep of updating the secondary events is not successful. In someembodiments, the writer (412) will serialize the event prior to writingthe event as a value for the event identifier key.

In the illustrated embodiment, the deduplication store (414) storesevents per batch period and per type of event. In some embodiments, thestore (414) creates a new table for each event type and batch periodpair for a fixed period of time (e.g., one week) since the current time.The store (414) additionally includes a pruning process thatperiodically inspects the created tables and removes older tables notoccurring within the current period (e.g., older than one week). In someembodiments, the auditor (310) initiates this pruning process uponconfirming that all data for a given period is certified.

The spooler (308) additionally includes a fact feed writer (416). In theillustrated embodiment, the fact feed writer (416) waits for a signalfrom auditor (310) to trigger a spooling process to write the events inthe store (414) to the fact feed (210) for a particular batch period andevent type. In one embodiment, the fact feed writer (416) includes aninternal web server that comprises a Hypertext Transfer Protocol (HTTP)endpoint that is called by the auditor (310) to initiate the spooling.As described above, once the auditor (310) confirms that the data in thestore (414) is fully processed and certified, the auditor (310) issues acall to the endpoint which causes the writer (416) to start writing tothe fact feed (210). In one embodiment, the writer (416) executes adistributed process routine to per from a full table scan of the store(414) and write the events to the fact feed (210).

For each event in the store (414), the writer (416) will deduplicate theevents prior to writing. In one embodiment, the writer (416) will firstdetermine if an event has one or more secondary identifiers and whetherthat secondary event was successfully joined to the event underinspection. If so, the writer (416) will select the most recentsecondary event and write that joined event to the fact feed (210).Alternatively, if the event under inspection indicates that a primaryevent is available, the writer (416) will skip the event (since a rootevent exists). Finally, if the event does not have secondary identifiersand the primary event flag is not raised, the writer (416) will writeout the event as failed since the secondary event was not properlyjoined.

In some embodiments, low-latency consumers may not want to or be able toconsume a low-latency stream (408 a) directly. For example, the streammight contain personally-identifiable fields that need to be restrictedto specific consumers or the final consumer may need additionalprocessing of events for their use. As another example, the consumer maybe consuming from many sources and is unable to handle different eventschemas of their various inputs. In these scenarios, the system (400)provides derived low-latency streams, or “filters”, that have all of theevents (or at least all of the desired events) as the second queue (408b) stream. Each filter can be associated with a quality of service (QoS)level. In the illustrated embodiment, three QoS levels are provided: “atleast once”, “at most once”, and “at least once with tag.”

A filter having an at least once QoS outputs every event but potentiallyincludes duplicates. In the event of a system (400) failure, the atleast once filter resends previously-sent events. A filter having an atmost once QoS does not include duplicates but potentially drops data.The at most once filter does not reprocess the same event batch morethan once.

Finally, a filter having an at least once with tag QoS generates batchdataset wherein each event in the batch includes tags allowingdownstream consumer systems to detect duplicates. In one embodiment,this filter includes a stream topic, partition, and a “cursor,” that canbe used to detect duplicates. In some embodiments, Kafka offsets and CMSMessage Ids could provide such cursors. The consumer system is thenresponsible for keeping track of the last cursor it processed, anddiscard any subsequent batch with a cursor less than or equal the newbatch. This requires a 1-to-1 correspondence between batches in thepipeline and derived streams.

Each of the above filters may be implemented via a separate streamprocessor (e.g., stream topology). In these embodiments, the filtersutilize an output of the system (400) (e.g., queues 408 a, 408 b) as aninput source (e.g., spout) and output the filtered feed.

For the at least one filter, the filter will always back up in the eventof a failure and resend any events that cannot be confirmed as beingsuccessfully delivered. This filter uses the initial spout (404) andstreaming queue (408 b) as inputs (e.g., filter spouts). In thisembodiment, the consumer is configured to not report its current readoffset. When sending data, the filter spout includes the current eventscursor in a message identifier. The receiver (e.g., sink) would thenacknowledge the received message only after successfully delivering thefiltered output to the derived stream. In some embodiments, the receivercould also use the existing spooler logic to fail a tuple if it can'tdeliver it, and then continue to fail subsequent tuples until itreceives a restarting indication from the spout. Upon receipt of anacknowledgement, the filter spout would commit that cursor back to thesystem (400). On receipt of a fail of a sent event, the filter spoutwould back up the received offset to a cursor at or before the lastacknowledged event and restart sending.

For the at most once filter, the filter spout enables automaticallycommitting offsets in a stream queue. By turning on auto-commitment, thefilter spout only transmits a given event once and does not re-transmitevents causing duplication.

For the at least once with tag filter, the at least one filter mechanismcan be used. However, in this filter, tags will be added prior totransmission to the consumer. These tags include the cursor, asdescribed above, but also a topic and partition if they aren't impliedby the derived stream's partition.

In some embodiments, an exactly once filter may be implemented based onthe at least once with tag filter. In this embodiment, a receiptacknowledgement message can be saved as reliably as the system (400) cansupport. Additionally, the filter, on receipt of the acknowledgement,could update some persistent record of the delivered cursor. However,persisting this data may be computationally expensive and requiresignificant storage. In an alternative embodiment, given the at leastonce with tag filter, the filter, on a start-up or after a failure, canaccess the output stream and read back a plurality of last-sent messagesin the queue. The filter could then determine the tag of the lastmessage written, then discard any replayed events from the spout untilit was caught up, thus ensuring exactly once delivery.

In some embodiments, the use of a single auditor (310) in the foregoingfigures may introduce latency to certain implementations of the system.Specifically, if it is known that a given pipeline (400) will perform anextensive number of join operations (e.g., joining more than three eventstreams together), a single auditor may introduce latency into theoverall pipeline. In the pipeline (400), when a topology performs a joinbetween a primary and secondary event, there is a requirement that theprimary events for time interval X are completely audited by an auditor(310) before the secondary events can start to be processed for the sameinterval X In short, if the audit step for a given interval takes tenminutes, then this results in a ten-minute delay before the secondaryevents can be processed by the same auditor (310). If there are threeevent streams, the delay for tertiary events increases to 20 minutes,etc.

To solve this problem and provide faster speeds even in the case ofmultiple join phases, the disclosed embodiments describe a modifiedauditor system to allow for parallel audit cycles between primary andsecondary event feeds. While described in the context of primary andsecondary events, the disclosed embodiments may be extended to anynumber of events. The disclosed embodiments allow for joins of manyfeeds to occur in parallel with minimal overhead, while also leveragingthe accuracy and speed of the other components of the pipeline (400)described above.

FIG. 5 is a block diagram illustrating an alternative auditor systemaccording to some embodiments of the disclosure.

By use of the auditor (310) and spooler (308), the pipeline (400)guarantees that for a given time interval X, if two replay-able andjoinable events P (primary) and S (secondary) are emitted from thepipeline (400), then the pipeline (400) guarantees that event S will beproperly annotated by event P (though it may produce a temporaryunannotated event S and replace it with a replayed annotated one at alater time). That is, the pipeline (400) will not produce an unannotatedsecondary event if the primary event it was to be joined with was alsoproduced on time. For example, given a click/impression join where theuser saw impression P and then clicked on the impression to produceclick S, the pipeline (400) should never produce impression P and anun-joined click S, no matter what order the events arrive and no matterwhat failures occur in the pipeline.

In some embodiments, the stream processor (304) includes a buffer formanaging the state of primary and secondary events. If a primary eventis received first, it is processed and emitted by the pipeline(identified herein as P). It is also cached for the incoming secondaryevent. When the secondary event is received it is annotated with thecached primary and emitted as a fully annotated secondary event(identified herein as S⁺). By contrast, in the out-of-order scenario,the secondary is received first and processed and cached. The emittedvalue (identified as S⁻) comprises an unannotated (or lonely) secondaryevent and is, in some respects, an improper value. When the primarylater arrives, the cached secondary is properly annotated and theprocessor (304) emits both P and S⁺. In some embodiments, when thestream processor (304) outputs the primary event in the out-of-orderscenario, it additionally writes a flag to the event indicating it wasprocessed out-of-order (this flag is referred to as a p-flag). At thisstage, the spooler (308) and auditor (310) process the events to ensurethat only S⁺ is written to the final fact feed as described above.

In the preceding pipeline (400), the only way for an audit to succeedand not produce a joined result is an out of order arrival (i.e., Sbefore P) followed by a dropped secondary. If the fully annotatedsecondary event (S⁺) is then lost during processing (e.g. due to asystem failure), then a normal audit of both feeds would succeed and theguarantee would fail.

However, in the illustrated embodiment, the auditor system (500) usesthe specially marked primary causes a flag to detect that joining of thesecondary was possible. However, if the p-flag was also dropped, theguarantee would fail. In some embodiments, the auditor system (500)ensures that the primary feed was audited first. If the primary feedsucceeded at its audit, the design of the pipeline ensures that thep-flag will reach the secondary queue.

In the illustrated embodiment, two auditors (502, 506) are connected toand receive raw events from the raw event storage (302). These twoauditors (502, 506) perform all of the functions described in connectionwith auditor (310) and those similar details are not repeated herein. Incontrast to pipeline (400), a primary auditor (502) is configured toaudit primary events while the secondary auditor (506) is configured toaudit secondary events. In some embodiments, the primary auditor (502)may also be configured to process any events not requiring a joinoperation. As mentioned, the auditor system (500) may include third,fourth, etc. auditors.

In the illustrated embodiment, the auditors (502, 506) arecommunicatively coupled to primary and secondary spoolers (504, 508).These spoolers (504, 508) perform the same functions described withrespect to spooler (308). However, as illustrated, each event type(primary, secondary) has its own respective spooler (502, 506). Asdescribed above, the auditors (502, 506) pull events to audit from thespoolers (504, 508) and compare these events to the corresponding rawdata from raw event storage (302). In contrast to pipeline (400), thesecondary auditor (506) is additionally coupled to a secondary spoolerprimary flag source (510). In the illustrated embodiment, the secondaryspooler primary flag source (510) comprises a data feed that consists ofthe p-flags generated during processing. Specifically, when the streamprocessor (304, not illustrated in FIG. 5) processes an out-of-orderjoin, the processor (304) adds a flag indicating as such (a p-flag). Inthe illustrated embodiment, the secondary spooler primary flag source(510) comprises a fact feed of just these p-flags. In some embodiments,the secondary spooler primary flag source (510) also include a join keyor other identifier. In contrast, to spooler (508), the secondaryspooler primary flag source (510) is significantly lighter weight andenables quicker processing of p-flags (discussed below).

In the illustrated embodiment, the primary auditor (502) outputs a finalprimary output (520) after auditing (and replaying, if necessary). Inthe illustrated embodiment, this primary fact feed comprises part of thefact feed (210). In one embodiment, the fact feed (210) may comprise aset of files corresponding to both batch intervals and event types.Thus, the output (520) may comprise a certified file for a primary eventtype in a given interval. In contrast to secondary events, the primaryevents may be certified immediately (or after replays) and do notrequire further join processing.

Although illustrated as a single process, the primary auditor (502) mayinclude one or more replay loops whereby primary events are replayed. Inthe illustrated embodiment, the primary auditor (502) should create apersistent signal as to whether or not any primary event was replayed atany replay level. As used herein, an audit is “clean” if no replays werenecessary at any level. In some embodiments, this information may bestored in a separate database (not illustrated) with a clean flag thatis initialized with true when the interval is started. If at any point areplay is required, the flag is updated to false. In addition, theprimary auditor (502) will record the timestamp of when the auditfinished.

In contrast, the output of the secondary auditor (506) comprise a draftoutput (512). This draft output (512) may be stored in a temporarylocation on disk separate from the certified events. The auditor (506)also outputs a second set of raw data highway (DH) events that were notproperly joined (e.g., lonely events).

In the illustrated embodiment, there is no dependency between when theprimary auditor (502) and secondary auditor (508) start. In oneembodiment, the secondary auditor (508) will create an auxiliary feed(514) containing the raw data highway records, this feed (514) includesall un-joined secondary events present in the raw data. In someembodiments, the entire raw event record is output so that theattributes are ready for replay if necessary. In some embodiments, thesecondary auditor (508) should record the timestamp that the audit beganin the database described above with respect to monitoring replaylevels.

In the illustrated embodiment, the auditor system (500) additionallyincludes a join audit check (516). In the illustrated embodiment, thejoin audit check (516) comprise the second phase of auditing ofsecondary events while the auditor (508) comprises the first phase. Inthe illustrated embodiment, this second phase of auditing the secondaryevents begins after the primary auditor (502) has published the finaloutput (520) and after the secondary auditor (508) has completed thedraft (512) and un-joined auxiliary file (514). That is, the join auditcheck (516) must await the first phase secondary auditor (508) tocomplete and the primary auditor (502) to complete. Additionally, thejoin audit check (516) waits for the secondary spooler primary flagsource (510) to account for all replayed primaries replayed during theprimary audit.

In some embodiments, the join audit check (516) must await every primaryaudit in every prior interval of the join window. For example, if thejoin look back window is one hour, then the second phase of secondaryauditing for five-minute interval 11:55 must depend on the primary auditbeing completed for all primary events from 11:00 to 11:55.

The join audit check (516) begins by checking the primary clean flag forall primary intervals whose audit completed after the secondary auditbegan. If a primary audit completed before the secondary started, thenthere will be no new p-flags written from that interval. Thus, the checkis unnecessary unless there exists at least one primary interval in thejoin window which was not clean (issued replays) and its audit did notcomplete until after the current secondary audit started. If no suchun-clean audit exists, then the join audit check phase may short circuitand report a pass.

Otherwise, there may be p-flags in the current interval that were notconsidered. If at least one interval was dirty, then the join auditcheck should proceed by performing an inner join on the p-flag feed andthe auxiliary feed. If the inner join fails to produce any joinedrecords, then the audit will have passed. If the inner join produces anyrecords, then the data highway record from the join should be writtenout to a replay queue and the join check should fail.

If the result of the join check passes, then control should be passed toa publishing step (518) which moves the draft secondary feed (512) tothe final published location (524). Upon a failed join check, the auditwill be considered a failure and the replay mechanism (522) shouldreplay everything in the replay queue, and then the entire audit fromthe secondary start should be retried just like normal.

FIG. 6A is a flow diagram illustrating a method for performing aparallel audit of events according to some embodiments.

As will be discussed, when both initial audits (referred to as existenceaudits) for primary and secondary events are complete for a giveninterval, it can be confirmed that all events that need to be writtenout by the pipeline have been spooled. Thus, the only reason to replaythe secondary events all events were received is if, for a givensecondary event identifier, there exists a p-flag and no joinedsecondary. In this scenario, the fully annotated secondary event wasdropped by the pipeline (400). For any given event identifier, there areonly certain combinations of records that can occur. Before discussingthe operation of the methods (600 a, 600 b), the following table isprovided that summarizes the possible combinations that the methods (600a, 600 b) handle.

TABLE 1 Raw S Replay or # (DH) S⁻ S⁺ p-flag Note Emit 1 True False FalseFalse Existence check failed Replay S 2 True False False True Existencecheck and Replay S join check fails 3 True False True False Joinedrecord exists Emit S⁺ 4 True False True True Joined record exists EmitS⁺ 5 True True False False No join possible False, emit S⁻ 6 True TrueFalse True Join check failed Replay S 7 True True True False Joinedrecord exists Emit S⁺ 8 True True True True Joined record exists Emit S⁺

In Table 1, the column “Raw S (DH)” refers to the presence of thesecondary event S in the raw event store and is set to true for allcases. The column S⁻ refers to the presence of an un-joined secondaryevent in the secondary event feed stored by the secondary spooler (506)and processed by the secondary auditor (506). The column S⁺ refers tothe presence of a fully annotated secondary event stored by thesecondary spooler (506) and processed by the secondary auditor (506).The column p-flag refers to whether a p-flag was raised in the secondaryspooler primary flag source (510) for a corresponding secondary event.The note column summarizes the case and indicates whether the joinedrecord properly exists in the draft output (512), whether the existencecheck (initial audit) failed, whether the join audit check (516) failed,or whether no join was possible.

As indicated in Table 1, there are three cases (#1, #2, and #6) where areplay is required. The first two conditions (#1 and #2) are failures ofthe existence check and are not influenced by the p-flag. That is, inboth cases, the secondary was wholly absent from the secondary spoolerfeed and thus the event should be replayed. The third replay condition(#6) is influenced by the p-flag. Specifically, since S⁻ was found andthe p-flag was raised, the system expects that S⁺ should have beenpresent during the out-of-order annotation. Similarly, case #5 can onlybe reached if it is known that all p-flags have been emitted, or ratherthat the primary audits have completed. Thus, it is this condition thatneeds to be reviewed by the second phase of the secondary event audit.In other words, the conditions for #5 may be a false positive for case#6 if the p-flags are missing. P-flag existence is guaranteed by theprimary audit, and thus, case #5 cannot be confirmed as a true #5 untilprimary audit is completed.

The most common reason without a node failure or similar issue is thatthe primary event is not delivered in time to the pipeline by datahighway. If the primary is lost somehow, then primary audit will replayit. If the secondary audit is in progress, then it will not consider thep-flag from the missing primary and thus could detect case #5 instead of#6 and fail to replay. Therefore, all case #5s need to be reviewed afterthe primary audit completes.

In step 602 a, the method (600 a) completes a primary audit. In theillustrated embodiment, the primary audit comprises a comparison of theprimary events processed by the system and is performed in the mannerdescribed in previous Figures. In brief, the primary audit confirms thateach processed event corresponds to a raw event in the raw event store.

In step 604 a, the method (600 a) publishes a set of primary events. Asdiscussed, the primary audit will publish a set of primary events afterconfirming the audit. In some embodiments, this publishing will beperformed after one or more replays of the primary events.

In step 606 a, the method (600 a) completes a secondary audit. In oneembodiment, although illustrated as occurring after the primary audit,the secondary audit may be started irrespective of the primary audit.That is, there is no dependency between the primary and secondary auditstarts. In the illustrated embodiment, the secondary audit may beperformed in a manner similar to the primary audit, albeit for secondaryevents. However, as part of 606 a, the method (600 a) generates anauxiliary feed containing the raw data highway records that satisfy case#5 above. That is, the method (600 a) in step 606 a creates a feed of S⁻events that do not include a corresponding p-flag raised. In someembodiments, the contents of the feed include the raw event fields fromthe corresponding raw event record (that is, the unprocessed eventfields in addition to the processed event fields)

In step 608 a, the method (600 a) performs a join audit check. In theillustrated embodiment, the output of the join audit check is a pass orfail. Details of the generation of this pass or fail result are providedin the description of FIG. 6B which is not repeated herein. As will bedescribed in FIG. 6B, the inputs to the join audit check include theauxiliary feed generated in step 606 a as well as the outputs of theprimary and secondary audit generated in step 602 a, 604 a. Thus, whilethe primary and secondary audits are not dependent to start in aspecific sequence, the processing in step 608 a must await the resultsof these feeds. Further, the method (600 a) must await the replay of allprimary events to generate a complete listing of p-flags.

In step 610 a, the method (600 a) receive the output of the join auditcheck performed in step 608 a and branches based on the result.

In step 612 a, the method (600 a) replays the secondary events if thejoin audit check signals a failing result. In one embodiment, the method(600 a) generates a list of errantly un-joined secondary events in step608 a and transmits these un-joined events to a replay mechanism. Thereplay mechanism then re-processes the un-joined events through thepipeline and the method (600 a) repeats.

Alternatively, in step 614 a, the method (600 a) publishes the resultsof the secondary audit if the join audit check signals a pass. In thisscenario, the join audit check signals that all of the events wereproperly joined. In some embodiments, this determination is made basedon a threshold. That is, the join audit check may determine if thenumber of failed joins is below a threshold. If so, the method (600 a)publishes the results of the secondary audit. In one embodiment,publishing the results of the secondary audit comprises copying theresults of the secondary audit to a final published location in adistributed file system.

FIG. 6B is a flow diagram illustrating a method for performing a jointaudit check according to some embodiments.

In step 602 b, the method (600 b) checks the p-flags for all primaryevent intervals whose audit completed after the secondary audit began.If a primary audit completed before the secondary started, then therewill be no new p-flags written from that interval. Thus, the check isunnecessary unless there exists at least one primary interval in thejoin window which was not clean (i.e., issued replays) and its audit didnot complete until after the current secondary audit started.

In step 604 b, the method (600 b) branches based on the foregoing check.If no such un-clean audit exists, then the method (600 b) may shortcircuit and report a pass signal (606 b). Otherwise, the method (600 b)proceeds to perform the full join audit check.

In step 608 b, the method (600 b) identifies one or more dirtyintervals. In the illustrated embodiment, a dirty interval refers to aninterval in a join window that includes one or more raised p-flags for acorresponding un-joined (S⁻) event. As described above, in somescenarios, the secondary existence audit may detect the presence of S⁻and no raised p-flag, which would indicate a lonely secondary event.However, during replay (or at some other point in the join window) thep-flag may be raised but S⁺ not found, indicating that S⁺ was lost afterjoining. If this occurs, the window including the event with the raisedp-flag is deemed “dirty.”

In some embodiments, the method (600 b) may not identify any dirtyintervals. In this scenario, the method (600 b) may emit the lonelyevent (S⁻) as the proper output.

In step 610 b, after identifying at least one dirty interval the method(600 b) performs in inner join on the p-flag feed and the auxiliaryfeeds. As described above, the auxiliary feed includes all raw secondaryevents (S⁻) satisfying case #5 while the p-flag feed will include lonelysecondary events with raised p-flags. Thus, the inner join operationproduces the overlap of these two feeds. That is, the inner join willinclude all S⁻ in the auxiliary feed that also correspond to events witha raised p-flag. If all events were replayed and corrected, the resultof the inner join will be equal to the auxiliary feed. If some eventswere not properly replayed, the result will be a subset of the auxiliaryfeed. In some embodiments, the inner join is performed on a shared joinkey.

In step 612 b, the method (600 b) determines if any records resultedfrom the inner join. If the inner join fails to produce any joinedrecords, then the audit will have passed and the method (600 b) willemit a pass signal (606 n). In the illustrated embodiment, the lack ofrecords indicates that any lonely events in the auxiliary feed are, infact, lonely secondary events and should be persisted as such.

In step 614 b, however, the method (600 b) detects one or more recordsin the inner join result. The presence of events in the inner joinresults means that at least one lonely event (S⁻) matched alater-identified p-flag. In this scenario, the method (600 b) determinesthat the annotated event (S⁺) was dropped by the pipeline. The method(600 b) then adds the raw secondary event record from the data highwayto a replay queue for reprocessing and emits a fail signal in step 616b. As described, the fail signal will prevent certification of thesecondary event data and the missing events will be re-processed. Insome embodiment, the methods (600 a, 600 b) will certify a partial eventset an only re-process those events resulting from the inner join.

FIG. 7 is a schematic diagram illustrating a computing device showing anexample embodiment of a client or server device used in the variousembodiments of the disclosure.

The computing device (700) may include more or fewer components thanthose shown in FIG. 7. For example, a server computing device may notinclude audio interfaces, displays, keypads, illuminators, hapticinterfaces, GPS receivers, cameras, or sensors.

As shown in the figure, the device (700) includes a processing unit(CPU) (722) in communication with a mass memory (730) via a bus (724).The computing device (700) also includes one or more network interfaces(750), an audio interface (752), a display (754), a keypad (756), anilluminator (758), an input/output interface (760), a haptic interface(762), an optional global positioning systems (GPS) receiver (764) and acamera(s) or other optical, thermal, or electromagnetic sensors (766).Device (700) can include one camera/sensor (766), or a plurality ofcameras/sensors (766), as understood by those of skill in the art. Thepositioning of the camera(s)/sensor(s) (766) on the device (700) canchange per device (700) model, per device (700) capabilities, and thelike, or some combination thereof.

The computing device (700) may optionally communicate with a basestation (not shown), or directly with another computing device. Networkinterface (750) is sometimes known as a transceiver, transceivingdevice, or network interface card (NIC).

The audio interface (752) produces and receives audio signals such asthe sound of a human voice. For example, the audio interface (752) maybe coupled to a speaker and microphone (not shown) to enabletelecommunication with others or generate an audio acknowledgment forsome action. Display (754) may be a liquid crystal display (LCD), gasplasma, light-emitting diode (LED), or any other type of display usedwith a computing device. Display (754) may also include atouch-sensitive screen arranged to receive input from an object such asa stylus or a digit from a human hand.

Keypad (756) may comprise any input device arranged to receive inputfrom a user. Illuminator (758) may provide a status indication orprovide light.

The computing device (700) also comprises input/output interface (760)for communicating with external devices, using communicationtechnologies, such as USB, infrared, Bluetooth™, or the like. The hapticinterface (762) provides tactile feedback to a user of the clientdevice.

Optional GPS transceiver (764) can determine the physical coordinates ofthe computing device (700) on the surface of the Earth, which typicallyoutputs a location as latitude and longitude values. GPS transceiver(764) can also employ other geo-positioning mechanisms, including, butnot limited to, triangulation, assisted GPS (AGPS), E-OTD, CI, SAI, ETA,BSS, or the like, to further determine the physical location of thecomputing device (700) on the surface of the Earth. In one embodiment,however, the computing device (700) may through other components,provide other information that may be employed to determine a physicallocation of the device, including, for example, a MAC address, InternetProtocol (IP) address, or the like.

Mass memory (730) includes a RAM (732), a ROM (734), and other storagemeans. Mass memory (730) illustrates another example of computer storagemedia for storage of information such as computer-readable instructions,data structures, program modules, or other data. Mass memory (730)stores a basic input/output system (“BIOS”) (740) for controlling thelow-level operation of the computing device (700). The mass memory alsostores an operating system (741) for controlling the operation of thecomputing device (700)

Applications (742) may include computer-executable instructions which,when executed by the computing device (700), perform any of the methods(or portions of the methods) described previously in the description ofthe preceding Figures. In some embodiments, the software or programsimplementing the method embodiments can be read from hard disk drive(not illustrated) and temporarily stored in RAM (732) by CPU (722). CPU(722) may then read the software or data from RAM (732), process them,and store them to RAM (732) again.

For this disclosure, a module is a software, hardware, or firmware (orcombination thereof) system, process or functionality, or componentthereof. A module performs or facilitates the processes, features, orfunctions described herein (with or without human interaction oraugmentation). A module can include sub-modules. Software components ofa module may be stored on a computer-readable medium for execution by aprocessor. Modules may be integral to one or more servers or be loadedand executed by one or more servers.

The terms “user,” “subscriber,” “consumer” or “customer” refer to a userof an application or applications as described herein or a consumer ofdata supplied by a data provider. By way of example, and not limitation,the term “user” or “subscriber” can refer to a person who receives dataprovided by the data or service provider over the Internet in a browsersession, or can refer to an automated software application whichreceives the data and stores or processes the data.

One of skill in the art may implement the methods and systems of thepresent disclosure in many manners. As such, the disclosed embodimentsare not to be limited by the preceding exemplary embodiments andexamples. In other words, functional elements being performed by singleor multiple components, in various combinations of hardware and softwareor firmware, and individual functions, may be distributed among softwareapplications at either the client level or server level or both. In thisregard, one may combine any number of the features of the differentembodiments described herein into single or multiple embodiments, andalternate embodiments having fewer than or more than, all the featuresdescribed herein are possible.

Functionality may also be, in whole or in part, distributed amongmultiple components, in manners now known or to become known. Thus,myriad software/hardware/firmware combinations are possible in achievingthe functions, features, interfaces, and preferences described herein.Moreover, the scope of the present disclosure covers conventionallyknown manners for carrying out the described features and functions andinterfaces. The scope of the present disclosure may also covervariations and modifications made to the hardware or software orfirmware components described herein as would be understood by thoseskilled in the art.

Furthermore, the embodiments of methods presented and described asflowcharts in this disclosure are provided by way of example to providea complete understanding of the technology. The disclosed methods arenot limited to the operations and logical flow presented herein.Alternative embodiments exist that alter the order of the variousoperations or include independent sub-operations that are part of a moreextensive operation.

While the disclosure describes various embodiments, such embodimentsshould not limit the teaching of this disclosure to those embodiments.Various changes and modifications may be made to the elements andoperations described above to obtain a result that remains within thescope of the systems and processes described in this disclosure.

What is claimed is:
 1. A method comprising: completing a first audit fora primary event type, the first audit generating a set of primaryevents; completing a second audit for a secondary event type, the secondaudit generating a draft set of secondary events and an auxiliary feedof un-joined secondary events; performing a join audit check on theauxiliary feed of un-joined secondary events and a set of flags, eachflag in the set of flags indicating that a respective un-joinedsecondary event was properly joined; and replaying a subset of theun-joined secondary events in the auxiliary feed upon determining thatthe join audit check failed.
 2. The method of claim 1, furthercomprising publishing the set of primary events after completing thefirst audit.
 3. The method of claim 1, further comprising certifying thedraft set of secondary events upon determining that the audit checkpassed.
 4. The method of claim 1, the performing a join audit checkfurther comprising performing an inner join operation on the auxiliaryfeed and the set of flags.
 5. The method of claim 4, the performing aninner join operation comprising performing an inner join based on ashared join key.
 6. The method of claim 4, the replaying the subset ofthe un-joined secondary events comprising adding a result set of theinner join operation in a replay queue.
 7. The method of claim 1, theperforming the join audit check further comprising identifying a dirtyinterval, a dirty interval comprising an interval in a join window thatincludes one or more raised flags in the set of flags for acorresponding un-joined secondary event.
 8. An apparatus comprising: aprocessor; and a storage medium for tangibly storing thereon programlogic for execution by the processor, the stored program logic causingthe processor to perform the operations of: completing a first audit fora primary event type, the first audit generating a set of primaryevents; completing a second audit for a secondary event type, the secondaudit generating a draft set of secondary events and an auxiliary feedof un-joined secondary events; performing a join audit check on theauxiliary feed of un-joined secondary events and a set of flags, eachflag in the set of flags indicating that a respective un-joinedsecondary event was properly joined; and replaying a subset of theun-joined secondary events in the auxiliary feed upon determining thatthe join audit check failed.
 9. The apparatus of claim 8, the operationsfurther comprising publishing the set of primary events after completingthe first audit.
 10. The apparatus of claim 8, the operations furthercomprising certifying the draft set of secondary events upon determiningthat the audit check passed.
 11. The apparatus of claim 8, theperforming a join audit check further comprising performing an innerjoin operation on the auxiliary feed and the set of flags.
 12. Theapparatus of claim 11, the performing an inner join operation comprisingperforming an inner join based on a shared join key.
 13. The apparatusof claim 11, the replaying the subset of the un-joined secondary eventscomprising adding a result set of the inner join operation in a replayqueue.
 14. The apparatus of claim 8, the performing the join audit checkfurther comprising identifying a dirty interval, a dirty intervalcomprising an interval in a join window that includes one or more raisedflags in the set of flags for a corresponding un-joined secondary event.15. A non-transitory computer-readable storage medium for tangiblystoring computer program instructions capable of being executed by acomputer processor, the computer program instructions defining the stepsof: completing a first audit for a primary event type, the first auditgenerating a set of primary events; completing a second audit for asecondary event type, the second audit generating a draft set ofsecondary events and an auxiliary feed of un joined secondary events;performing a join audit check on the auxiliary feed of un joinedsecondary events and a set of flags, each flag in the set of flagsindicating that a respective un-joined secondary event was properlyjoined; and replaying a subset of the un-joined secondary events in theauxiliary feed upon determining that the join audit check failed. 16.The computer-readable storage medium of claim 15, the instructionsfurther defining the step of publishing the set of primary events aftercompleting the first audit.
 17. The computer-readable storage medium ofclaim 15, the instructions further defining the step of certifying thedraft set of secondary events upon determining that the audit checkpassed.
 18. The computer-readable storage medium of claim 15, theperforming a join audit check further comprising performing an innerjoin operation on the auxiliary feed and the set of flags.
 19. Thecomputer-readable storage medium of claim 18, the performing an innerjoin operation comprising performing an inner join based on a sharedjoin key.
 20. The computer-readable storage medium of claim 18, thereplaying the subset of the un-joined secondary events comprising addinga result set of the inner join operation in a replay queue.